1. Technical Field
This invention relates to emergency fire fighting and rescue systems for high-rise buildings, and particularly to systems that incorporate an outside elevator using an exterior track on an outside wall of the building.
2. Background Art
Various exterior elevator escape systems for rescuing people from fires or other emergencies in multistory buildings have been proposed for decades. Within the past ten years or so there has been renewed interest in such systems as the result of several major fires in high-rise hotel and office buildings.
The proposed systems are of two principal types, relatively simple evacuation systems, in which individual harnesses or passenger cars are stored at each floor of a building on spurs of a slide track to carry individuals or groups to the ground under the influence of gravity, and more complex true elevator systems, in which cars or gondolas depart from and return to ground.
U.S. Pat. No. 3,944,021 of SMITH, Jr. et al. discloses a gravity escape system that includes a transfer feeder line between two fire escape mechanisms on respective upper and lower building sections that are separated by a setback.
The more sophisticated elevator type of systems use cable hoist or rack and pinion drives for raising and lowering cars. All of the gear drive mechanisms support the car on vertical rails, using guide wheels separate from the drive pinions to support and stabilize the car on the rails.
Power for operating these exterior elevators usually comes from portable generators that are installed in emergency vehicles that may also bring the elevator gondola to the scene from a central station. The electricity from the generator may be delivered to electric drive motors in the rail car either through cables or through bus bars permanently attached to the guide rail on the building. Power may also be available from a supply at the building, or the rail car may have its own engine. Examples of such external elevator systems are disclosed in U.S. Pat. Nos. 4,018,306 of LYONS; 4,469,198 of CRUMP; 4,569,418 of NOVARINI; and 4,664,226 of CENTANNE.
All of the vertical rail external elevator systems of which the applicant is aware are intended to operate a rail car on a single rail or pair of rails extending in a vertical plane to the top of a building. Many highrise buildings, however, are built with one or more setbacks, in accordance with building codes to provide sufficient light and air at ground level. The setbacks on such buildings present a problem for reaching the floors in the upper smaller area sections because the prior art exterior elevator systems provide no way for a rail car to transfer from a first vertical rail or rails, negotiate a lateral setback and then engage with and continue to climb a second vertical rail or rails on the upper section of a building.